Hydrocephalus is a condition afflicting patients who are unable to regulate cerebrospinal fluid flow through their body's own natural pathways. Produced by the ventricular system, cerebrospinal fluid is normally absorbed by the body's venous system. In a patient suffering from hydrocephalus, the cerebrospinal fluid is not absorbed in this manner, but instead accumulates in the ventricles of the patient's brain. If left untreated, the increasing volume of fluid elevates the patient's intracranial pressure and can lead to serious medical conditions such as subdural hematoma, compression of the brain tissue, and impaired blood flow.
The treatment of hydrocephalus has conventionally involved draining the excess fluid away from the ventricles and rerouting the cerebrospinal fluid to another area of the patient's body, such as the abdomen or vascular system. A drainage system, commonly referred to as a shunt, is often used to carry out the transfer of fluid. In order to install the shunt, typically a scalp incision is made and a small hole is drilled in the skull. The proximal end of the shunt, which usually includes a proximal, or ventricular, catheter, is installed in the ventricular cavity of the patient's brain. The distal end of the shunt, which includes a distal, or drainage, catheter, is installed in that portion of the patient's body where the excess fluid is to be reintroduced. To regulate the flow of cerebrospinal fluid and maintain the proper pressure in the ventricles, a pump or valve can be placed between the proximal and distal catheters. If the pump or valve is not equipped with anti-siphon features and such features are desirable, a siphon control device can be separately included. The siphon control device can be positioned within the fluidic pathway, usually between the shunt valve and the drainage catheter. The siphon control device avoids overdrainage caused by the siphoning effect of hydrostatic pressure in the distal shunt catheter, which can be created by the elevation of the proximal catheter inlet with respect to the distal catheter outlet, i.e., when the patient sits or stands.
In most conventional shunt systems, the various components that form the shunt system, i.e., proximal and distal catheters, shunt valve, anti-siphon device, tubing, etc., are manufactured separately and then connected together during implantation to form the complete drainage pathway. During a typical surgical procedure, the proximal catheter is inserted directly into the ventricle cavity, after which the shunt valve and a pre-attached distal catheter are then implanted near the surface of the skull at an approximately 90° angle with respect to the proximal catheter. The proximal catheter is then attached by means of suturing surgical tubing to an inlet port on the shunt valve, thereby forming a right angle with respect to the shunt valve. With the current increase in popularity of endoscopic surgeries, some neurosurgeons have now attempted rigid endoscopic placement of ventricular catheters into the ventricles of the brain. In some cases endoscopic placement of shunt valves having domed silicone reservoirs with attached pre-cut catheters has even been attempted.
Because of the limited space available for the surgeon to perform the suturing after the proximal catheter is advanced into the ventricles, the assembly procedure after endoscopic implantation of the shunt system components can be extremely difficult. Also, shunts having domed reservoirs are not easily occluded for flushing distally. Given the amount of time necessary to suture the surgical tubing that connects the ventricular catheter to the shunt valve, the length of the surgical procedure can prove to be less than desirable. An added setback to using these conventional shunt systems is the compatibility problems that arise when the various components are produced by different manufacturers. Furthermore, currently available shunt systems can be prone to shunt separation and/or leakage at the sites where the separate components are connected to one another via the surgical tubing.